Five U.S. soldiers were killed in central Iraq on Monday, Pentagon officials said. No additional details were given, including the cause of death.

According to unnamed Iraqi security officials, a barrage of at least three rockets hit an Iraqi base in eastern Baghdad on Monday morning, killing the five American soldiers. The troops were staying at the Iraqi base as advisers.

According to an Associated Press report, the latest attack brings the number of American service members killed in Iraq to 4,459.

Monday's attack is the single largest loss of life for the U.S. military in Iraq since 2009, when five U.S. troops were killed in Baghdad.

Meanwhile, retiring Defense Secretary Robert Gates, who is in Afghanistan to bid a final farewell to frontline U. S. troops, said it's still too soon to wind down the war there.

According to Gates, the death of Osama bin Laden will not convince the Afghan Taliban to back down.